The industry of computer telephony has experienced extensive growth over the last several years. One aspect of computer telephony involves software computer telephony applications which communicate over a local area network (LAN) or computer bus with a computer telephony (CT) server. The CT server then communicates with a private automated branch exchange (“PABX” or “PBX”) for the purpose of implementing certain computer telephony functions. For example, “screen pop” is an example of a computer telephony application which may run on a personal computer (PC) and which may be implemented using a computer telephony server. In such an arrangement, a caller who dials in to a call center would have his telephone number read by a PBX. The telephone number is then forwarded through a local area network to a CT application program, which utilizes a table look-up in order to map the telephone number to a particular account number and account information. The account information is then read from a database and placed upon a computer screen to make it available to an agent for handling the incoming telephone call.
U.S. Pat. No. 5,414,762 assigned to Q-sys describes a computer telephony server that can be implemented as a layer of software and assists with the interface between various PBXs and applications. Specifically, as described in the Q-sys patent, each of the variety of PBXs available on the market today may have differences in its command set, message structure and other features. Accordingly, it is highly desirable that applications developers who write CT applications be able to write such applications independent of the particular PBX being utilized. Otherwise, each time an application is to work with a different PBX, the application would have to be rewritten.
The foregoing Q-sys patent solves the problem by offering a CT server that is capable of communicating with a variety of PBXs available on the market. The Q-sys telephony server has a standard message structure for communicating with applications over a local area network or a computer bus. Additionally, the arrangement taught by the Q-sys patent provides a means for translating the messages received from CT applications into the particular language and message structure of the particular PBX being utilized by the system.
The arrangement of the Q-sys patent provides a solution to the problem that applications developers used to face, namely, that each time their application was connected to a different PBX, it would have to be rewritten in order to understand and interpret the particular message structure, protocol, etc., of the PBX. By utilizing the Q-sys technique, a common language can be used by all applications, and a layer of independence is achieved between the CT application and the PBX. Systems like that taught by the Q-sys patent were available nearly ten (10) years ago from Digital Equipment Corporation.
One problem with the Q-sys arrangement is that it does not take into account the fact that a PBX is only one particular type of telecommunications system capable of establishing a call between users. Specifically, the Q-sys system, while being capable of communicating with a variety of PBXs, is limited to situations where a PBX is the means by which arriving telephone calls are connected to users. In view of the foregoing, there exists a need in the art for an improved CT server which can operate in an environment where there are not only PBXs being utilized to establish calls between users, but rather, where a variety of telephony systems (packet telephony networks, public switched telephony networks, etc.) may be utilized alternatively or simultaneously to construct such cells.